The present invention relates to equipment used in well drilling operations including, but not limited to, a top drive, a lower well control valve, a manual valve, and a saver sub. The top drive travels up and down along the torque guide in the mast. The torque guide transmits the drilling reactive torque to the mast. The top drive has a center quill that typically has a threaded connection to attach to the drill string. The quill typically has an API thread at the attachment of the drill string and blow out preventer. The threaded connection is designed to withstand drilling torque, drill string make-up and breakout torque and tensile load generated by lifting the entire weight of the drill string. Depending on the application, over time, the threads of the quill may fail due to fatigue and/or external bending loads. Excessive bending loads and/or material defects in the quill may generate tensile cracks in the threads and cause enormous and costly down time due to a number of factors. First, the down time associated with failure of the quill connection can be significant, as the entire quill must be removed before a re-cut can occur or a replacement can be installed. The top drive itself may require partial disassembly in order to replace the quill. Second, due to the extensive size and weight of the quill, handling charges and repair bills can be significant. Additionally, the replacement cost of the quill is very high due to its size and complexity of manufacturing.